A 2 5GHz fully integrated LC VCO is fabricated in a standard single poly 4 metal 0 35μm digital CMOS process,using a complementary cross coupled topology for lowering power dissipation and reducing the effect of 1/ f noise.An on chip LC filtering technique is used to lower the high frequency noise.Accumulation varactors are used to widen frequency tuning.The measured tuning range is 23 percent.A single hexadecagon symmetric on chip spiral is used with grounded shield pattern to reduce the chip area and maximize the quality factor.A phase noise of -118dBc/Hz at 1MHz offset is measured.The power dissipation is 4mA at V DD =3 3V.